Sure I think there's some truth the that. You've gotta learn the rules first to know when it's ok break the rules. Somebody with a lot of experience should be able to judge how their message will be received, and what amount of effort is "good enough". Whereas someone with less workspace experience may lack such judgement, and is probably better off erring on the side of "too good" rather than "not good enough".

But it's definitely also very much tied to status, power, and privilege. The same people who have no qualms about firing off a sloppy email to their subordinates often spend a lot more effort on emails to their bosses. But even this discrepancy is justified, I think, given that a manager represents their subordinates to the higher ups. And the potential consequences of a bad impression or misunderstanding are more severe when communicating up the chain of command.